Comenius

PROGRAMME

Article Index
Impacts
Page 2
Page 3
Page 4
All Pages

Impacts

Stratosphere

There is now evidence that greenhouse gases are eroding the upper atmosphere (stratosphere) causing it to decrease in size. This could result in a decrease in the ozone layer which protects us from the sun’s ultra violet rays.

Sandstorms

These are increasing in China due to lower snow cover and precipitation in Mongolia and stronger winds causing dust storms to reach the capital Beijing

Glaciers

Recent studies show that these are melting at twice the rate of 20 years ago. This acceleration will initially cause flooding downstream, but subsequently there will be less melt water for people to use. This is a particularly severe problem for rivers which are fed from the Himalayan glaciers on which 1.7 billion people depend.

The other concern associated with melting glaciers is the growth of glacial lakes, which are increasing number and size. When these lakes reach a certain size, there is a risk of their dam wall collapsing giving rise to catastrophic floods downstream.

Rising global temperatures

An average 1º C temperature rise has already been observed since the start of the industrial era (ca 1750), and if this trend is continued, irreversible changes in climate could occur. Based on existing scientific evidence, the IPCC has recomanded that it is essential to limit the average global temperature rise to 1.5º C.

Whilst an average temperature rise of 1.5º C might not seem a lot, the fact is that such temperature rises are not uniformly distributed throughout the globe. Polar regions have experienced much higher temperature rises leading to concerns about melting ice sheets, rising sea levels and changes in the circulation of ocean currents particularly in the Arctic region.

Extreme weather conditions

Other predictions of climate models suggest more extreme weather conditions – these include tropical storms, extreme heat and cold, flooding and droughts. Such events have occurred with increasing frequency in the past decade with loss of lives, crops and livestock.
[link to adaptation]

Shifts in rainfall

An equal concern is possible shifts in rainfall (precipitation) in sub-arid areas like the Sahel area if Africa which may require inhabitants to migrate to other areas which are already inhabited. In previous eras when the climate changed, migration was possible because there was a small global population.

Melting of glaciers

It is widely acknowledged that glaciers are sensitive to climate change and there is substantial evidence of glaciers retreating ever since the end of the Little Ice Age associated with the years 1600 to 1700. Measurements from satellite images reveal that 94% of the glaciers have retreated, 4% exhibited no overall change and 2% have advanced.

melting of glaciers

In the Himalayan mountain range which stretches for 1200 miles in Asia, the melting of the glaciers has doubled in the past 20 years with more than a quarter of all ice lost over the past 40 years.
Glaciers in the Caucasus mountains of Asia which are receding.


The analysis led by Joshua Maurer shows that 8 billion tonnes of ice are being lost each year and not being replaced by snow with the lower level glaciers shrinking in height by 5 m annually. Their study also shows that only global heating caused by human activity can explain the heavy melting observed.

A report published in February 2019 concluded that ‘at least one third of the ice in the Hindu Kush-Himalaya ranges were already doomed to melt by the end of this century even if action was taken now to limit carbon emissions rapidly. Without action, two thirds would go’.

Melting glaciers will contribute to the mean rise in sea level along with thermal expansion of the oceans due to rise in sea temperature.

The other global concern of the continuing retreat of the glaciers with much more serious consequences is that many communities, comprising more than 1 billion people, are dependent upon melt water to provide water for themselves and their crops. The rivers that would be most affected are those fed by the melt waters of the Himalayan glaciers include the Ganges, Brahmaputra and Yellow rivers which flow through countries with large populations including Pakistan, India, Bangladesh and China.

Reference Melting of Himalayan glaciers doubles in 20 years Guardian newspaper 20/06/2019

Tropical rainforests

The tropical rainforests form a very important part of the Earth’s eco systems for the following reasons –

  • over half the world’s plants and animal species are found in them
  • the Amazon rainforest alone releases 20 billion tonnes of moisture every day, helping to water crops thousands of kilometres away
  • healthy rainforests absorb up to 10% of mankind’s carbon emissions each year through photosynthesis and storing carbonaceous products in plants, trees, roots and soils; up to 100 – 300 tonnes of carbon per hectare can be stored

tropical rainforest

These types of forest are very susceptible to any substantial rise in average temperature so die back of the forests will occur as the temperature continues to rise so diminishing their ability to regulate the climate. However these forests face an even more serious short term threat than climate change that is deforestation.

Typical area of rainforest showing diversity of vegetation

In the past deforestation was associated with the subsistence activities of local people. They cleared native forests to grow crops or to provide firewood, charcoal or timber for construction. These products were either consumed by families or traded locally.


Increasingly however more and more deforestation is being driven by commercial operators linked to global markets. Much of the beef, soya and palm oil produced in tropical countries is exported and ends up on our supermarket shelves, in our restaurants or to produce biodiesel.

One third of the tropical forests have been lost in the past 50 years and at current rate of usage, we could lose almost all of the rainforest in the next 50 years. This could have very severe consequences for our global climate as well as biodiversity. The trees in these forests are very susceptible to any significant increase in temperature; die back of the tree cover will start to occur if the average temperature rise exceeds 2°C.

The other threat to the rainforest is through global warming and changing rainfall patterns which could limit the growth of its biomass.

Coral reefs
Sometimes climate change in combination with other factors can also induce change in ecosystems. For example, three quarters of the world’s coral reefs are at risk from over fishing, pollution as well as climate change. By 2050 virtually all of the world’s coral reefs from the waters of the Indian Ocean to Australia will be in danger. Some 275 million people live within 30 kilometres of reefs which provide an important habitat for fish.

The most visible impact is the decay of coral reefs found in tropical areas of the world which fringe many of the shores in the shallow continental margins. These reefs are affected by both the increase in surface temperature and the rising acidity of the sea water which is of great concern as these coral reefs provide a home to 500,000 species, more than any other marine ecosystem.

KITH # Activity Age range
1.3  Impacts of changing climate   
 Science, citizenship, geography
 9 – 14 
1.4  Consequences of global warming  
 Science, citizenship, art
 9 – 14 
1.9   Glacier melting  
 Geography
 9 – 14 

Other activities

What local changes have you noticed in the climate? Also ask your parents or grandparents what changes they have observed?
What impact could global warming have on your local environment and way of life?
Do you think that such changes will continue to occur and if so why?
What local actions can you suggest to limit the impact of a changing climate? Design a poster to illustrate your suggestions.


poster

Climate change poster by Matthew Johnson

 

Search

Language Selection

Find us on